Chimney draft device with two fans



May a, 1923.

E. PRAT CHIMNEY DRAFT'DEVICE WITH TWO FANS Filed April 27. 1921 EMILEraa'nor PARIS, raanon, Assrenoia T0 soonirn DES A. TIRAGE rnnurr, orrears, raanon.

Farr i Q,

onnnrnnns Louis PRA'I.

CHIMNEY DRAFT DEVICE WITH TWO FANS.

Application filed April 27, 1921'. Serial No. 464,950.

To all whom it may concern:

Be it known that I, EMILE of the Republic of France, residing atParis,France, 64: Rue de Miromesnil, have invented certain new. and usefulImprovements in Chimney Draft Devices with Two Fans, of which thefollowing is a specification.

My invent-ion relates to induced draft devices of the type described inmy pending application Serial No. 370,860 filed April 2nd. 1920, inwhich a fan is arrangedwholly PHAT, a citizen inside the chimney and isstream-lined, i. e.

has theouter form of-a body of least resistance to the flow of gasespassing round it. In important draft plants it is further known toemploy two fans instead of one, in particular in order to have a sparefan or a second fan available when the action of one fan is to bereinforced. Insuch case, according to my present invention, the lowerpart of the two fans is terminated by a curved plate forming a hoodwhich gives the casing of the set of two fans the stream-lined form orform of a body of least resistance to the flow of gases deflected bysaid hood.

My invention further permits tion of the orifice of thetwo fans by meansof a movable ring inside the outlet nozzle common to the two fans,- saidring being adapted either to prolong the nozzle or to allow the passageof the gases both inside the ring and between the latter and the nozzle.

A further feature of the invention is that the partition common to thedischarge ducts of the two fans is made movable so as to control theconnecting of the fans in parallel or the shutting of either fan.

In the appended drawing which shows schematically two embodiments of theinvention. Figure 1 is a sectional elevation of a chimney having twoinner fans; Figure 2 is a sectional elevation at right angles to Figure1; Figure 3 is a sectional elevation showing details of the ring and theregulating movable partition or shutter; Figure 4 is a similar view of amodified form of the arrangement when the two fans'are placed in twodifferent planes instead of being in the same plane as in Figure 1;Figure 5 is a see tional elevation at right angles to that of Figure 4:.

Referring first to Figures 1 and 2, the two fans a a, are located insidethe chimney on a common median plane, their discharge ducts 0 0 openinginto a nozzle (1 common to both,

the regula- The casing of the two fans is surrounded, at its lower part,with a curved plate 6 forming a hood which gives the set of two fans theform designated in aeronautics as the stream lined form or body of leastresistance to the iiow of gases.

The gases are deflected by said plate to both sides of the set of fansand flow up the chimney with the smallest possible loss of pressure. i

The regulation of the gas delivery ofthe two fans is effected by meansof a movable conical ring f shown in Figures 3, i and 5, which isprovided with any suitable device enabling it to be raised and lowered.

When said ring is in the position shown in full lines, the two fansdischarge the fluid in parallel on a total area corresponding to theupper opening of nozzle (Z. On the contrary, when one of the fans isstopped the.

ring is raised to the position f shown 'indot and stroke lines; the fanthat remains in operation discharges on an orifice corresponding to theupper opening of said ring. In the intermediary positions of the ring,the two fans discharge on'a total orifice corresponding to an areaintermediate the upper openings of ring f and nozzle d. I i

It is known that the sett-ing'of fans in parallel is extremelydifficult,'as surging between them occurs when they work on a nozzlecommon to both. In order to avoid this inconvenience the discharge ducts0 c, of the two fans-have a common partition formed by shutter g (Figure3) for instance, adapt- 7 about a hinge 72,. According to requir'ements,to obtain regulation, the shuted to rock ter 9 is inclined either toright or to left hand. The end positions 9 or g, of the shuttercorrespond to stopping of either fan.

In the modified form of Figures i and 5, the shutter g, is in a planeperpendicular to the shutter of Figure 3. The discharge ducts c, and a,of the two fans are adjacenteach other instead of being opposite while"the nozzle (5 and ring f. are the same as in Fig. 3. The regulating ringand movable shutter of Figures 3. 4t and 5 can also be applied to I fansplaced outside a chimney and blowing atmospheric air into the latter.

What I claim is:

1. In combination, a chimney and a draft device associated with saidchimney, said draft devicecomprising a plurality of fans having separateinlets arranged side by side.

a 1,e54,5eo

2. In combination, a chimney, and a draft device associated with saidchimney, said draft dev ce comprising a plurality of fans arranged; sideby si'de and wholly within mit passage of a portion of the combustiongases and adapted to work in parallel and a single curved deflectingplate common to the two fans to form a stream line tothe respective faninlets.

v .4." In'combination, a chimney, and a'draft -device" associated withsaid chimney, said draft device comprising a plurality of fans havingseparate inlets and arranged wholly I .lIlSlCle otsaid chimney and beingspaced "therefrom to permit passage of a portion of fthecombustion gasesand adapted to work in parallel and a single substantial U-shapeddeflecting plateeommon to the several fans 'and"arranged at the ends ofthe latter pre sentedto the oncoming stream of combustion 'gases.

In combination, a chimney, and a draft device associated with saidchimney, said draft device comprising a plurality of fans arranged sideby side and each having a separate inlet,"and a curved hood partiallyenveloping the portions of the several we Cal ings 'presented to theflow of combustion "gases to form a stream line to the respective faninlets.

6. In combination, a chimney, and a draft to draw'in parallel a'portiononly of the combustion gases passing through the chimney, a dischargeduct on each fan, a single nozzle common to both discharge ducts, andmeans for causing said fans to work in parallel, 'saidmeans comprising apartition adapted to occupy a variable position between the two ducts tovary the ratio of the passage area. of said ducts.

7:111 combination, a chimney, a*'draft device associated with saidchimney, said draft device comprising twofans adapted to draw togetherapor ion only of the combustion gases passing through the chimney,

said fans being arranged wholly inside the chimney, and the remainder ofthe gases passing outside ofthefans directlyupthe chimney, adischargeduct' foreach fan, a

nozzle common to the discharge ducts of both fans for inducing the draftof said remainder of gases, and a mova-ble partition between saiddischarge ducts for varying the ratio of the outlet areas of'saidducts", said partition being adapted to he "placed in variable positionsbetween total opening and closing oi either duct.

8 In combination, a chimney, and a chimney draft devicegsaid draftdei'ice comprising two fans adapted to'di'aw together only aportion ofthecombustion gases passing through the chimney said fans being arrangedwholly in sidethe chimney andthe remainder of said gases passing outsidethe fans directly up the chimney, a discharge duct for each fan,anoz'zle common to the discharire ducts of both tans for inducing; thedraft. of said remainder of the gases, a movable partition"between thedischarge ducts for varying the ratio'of'the outlet area of said ducts,and a hood arranged overthe lower part of both 'itaiis' and curt-ed tostream-line them as to a \VllOlQ to thegases passin g outside them.

9. In combinatioma chimney, and a draft device associated with saidchimney. said draft device comprising a? plurality ot'fans capable ofindependent or simultaneous open ation and each having" a permanentlyopen inlet of constant area. k

In testimony whereof I aflix my signature.

7 EMILE PRAT.

